Techniques for getting to the truth

Do not interrupt them. Let them talk and encourage continuation, for
example with
pauses.

Ask them to tell their stories backwards to increase the cognitive load
(possibly overloading them).

So what?

When you are confronted with a potential liar, as well as other methods,
focus on the observations above. Note that these are not everything and that if
a person shows one or two behaviors this does not mean they are lying.